Rbs, rnc and respective methods performed thereby for transmitting data to a ue

ABSTRACT

A Radio Base Station (RBS) and a method performed by the RBS comprises receiving a frame F 1  from a network node, the frame having a sequence number N. If the last received frame F 0 , prior to the received frame F 1 , has a sequence number lower than N−1, then starting a first timer T 1  having a predefined length in time and temporarily storing the received frame F 1 . If a subsequent frame F 2  having a sequence number lower than N and higher than the sequence number of frame F 0  is received, then the received frame F 2  is stored. When all frames having a sequence number between the sequence number of frame F 0  and N have been received during the predefined length of the first timer T 1 , then forwarding the stored frames and/or received frames to the UE in the order of the sequence numbers.

TECHNICAL FIELD

The present disclosure relates to wireless communication network and inparticular to a Radio Base Station, a Radio Network Controller andrespective method performed thereby for transmitting data to a UserEquipment.

BACKGROUND

In a wireless communication system or wireless communication network,e.g. based on Wideband Code Division Multiple Access, WCDMA, the RadioNetwork, RN, typically comprises of one or more Radio NetworkControllers, RNCs, each connected to one or more Radio Base Stations,RBSs, where the latter are responsible for transmitting data over theair interface. For High Speed Downlink Packet Access, HSDPA, packet datais sent via a Transport Network, TN, between these nodes. For HSDPA theTN is either Asynchronous Transfer Mode, ATM, or Internet Protocol, IP,based.

In the latter case, there may be a chance that the ordering of thepackets received at the destination is different from that which thesender generated. This means that data arrives Out Of Sequence, OOS, inthe RBS.

In self-built or leased backhaul, an operator has good control over thetransport solution and OOS may not be expected. However, this is not thecase in Heterogeneous Network, Hetnet, deployments where the operatormight use public Internet Service Provider, ISP, network(s) forconnecting RBSs.

There are different causes for OOS like packet-level load sharing, routefluttering, router forwarding lulls, parallel processing in routers,improper configuration, and/or faulty software, etc.

Packet-level load sharing: if links have same link weights to thedestination, a router equally splits the traffic among these routers.

Route fluttering: forwarding path to a certain destination oscillatesamong a set of available routes to that destination.

Router forwarding lulls: some routers may pause its forwarding activityfor buffered packets, e.g. when they process a routing update. Thesebuffered packets are interspersed with new arrivals, thus causing packetreordering.

If data is received OOS in RBS and no attempt to correct this is donebefore data is further processed or conveyed to higher layers in a UserEquipment, UE, then a number of negative impacts may be expected. Theseare OOS delivery of messages to higher layers in UE, unnecessary RadioLink Control, RLC, Acknowledged Mode, AM, retransmissions and erroneousdecisions for TN Flow Control, FC.

SUMMARY

The object is to obviate at least some of the problems outlined above.In particular, it is an object to provide an RBS and a method performedby the RBS for transmitting data to a UE, the RBS receiving frames froma network node by means of an RLC protocol. It is further an object toprovide an RNC and a method performed by the RNC for transmitting datato a UE, via an RBS employing a transport protocol, the RNC transmittingdata by a series of frames to the RBS to be forwarded to the UE. Theseobjects and others may be obtained by providing an RBS and an RNC and arespective method performed by an RBS and an RNC according to theindependent claims attached below.

According to an aspect a method performed by an RBS for transmittingdata to a UE, the RBS receiving frames from a network node by means ofan RLC protocol is provided. The method comprises receiving a frame F1from the network node, the frame having a sequence number, N. If thelast received frame F0, prior to the received frame F1, has a sequencenumber lower than N−1, then the method comprises starting a first timerT1 having a predefined length in time and temporarily storing thereceived frame F1. If a subsequent frame F2 having a sequence numberlower than N and higher than the sequence number of frame F0 isreceived, then the received frame F2 is stored. When all frames havingsequence number between the sequence number of frame F0 and N have beenreceived during the predefined length of the first timer T1, then themethod comprises forwarding the stored frames and/or received frames tothe UE in the order of the sequence numbers.

According to an aspect, an RBS adapted for transmitting data to a UE,the RBS receiving frames from a network node by means of an RLC protocolis provided. The RBS comprises a processor and a memory, the memorycomprising instructions which when executed by the processor causes theRBS to receive a frame F1 from the network node, the frame having asequence number, N. The memory further comprises instructions which whenexecuted by the processor causes the RBS to start a first timer T1having a predefined length in time and temporarily store the receivedframe F1, if the last received frame F0, prior to the received frame F1,has a sequence number lower than N−1; and if receiving a subsequentframe F2 having a sequence number lower than N and higher than thesequence number of frame F0, then to store the received frame F2. Thememory further comprises instructions which when executed by theprocessor causes the RBS to forward the stored frames and/or receivedframes to the UE in the order of the sequence numbers, when all frameshaving sequence number between the sequence number of frame F0 and Nhave been received during the predefined length of the first timer T1,then to forward the stored frames and/or received frames to the UE inthe order of the sequence numbers.

The RBS and the method performed thereby may have several advantages.One possible advantage is that frames may be delivered in the correctsequence order and a possible OOS may be avoided. The method, or RBSfunctionality, has no impact on other nodes or entities than the RBS,hence only a software update of the RBS is required to upgrade the RBS.The method and the RBS may simplify the use of e.g. IP based solutionsfor the traffic network, which may be of particular importance forHetnet solutions.

According to an aspect, a method performed by the RNC for transmittingdata to a UE, via a RBS employing a transport protocol, the RNCtransmitting data by a series of frames to the RBS to be forwarded tothe UE is provided. The method comprises comprising receiving anotification from the RBS indicating that an Out Of Sequence hasoccurred for the series of frames; increasing a frame size in order toreduce the number of frames; and transmitting the data using theincreased frame size.

According to an aspect, an RNC adapted for transmitting data to a UE,via a RBS employing a transport protocol, the RNC transmitting data by aseries of frames to the RBS to be forwarded to the UE is provided. TheRNC comprises a processor and a memory, the memory comprisinginstructions which when executed by the processor causes the RNC toreceive a notification from the RBS indicating that an Out Of Sequencehas occurred for the series of frames; to increase a frame size in orderto reduce the number of frames; and to transmit the data using theincreased frame size.

The RNC and the method performed thereby may have several advantages.One possible advantage is that frames may be delivered in the correctsequence order and a possible OOS may be avoided. The RBS functionalityhas no impact on other nodes or entities than the RBS, hence only asoftware update of the RBS is required to upgrade the RBS. The RBS maysimplify the use of e.g. internet grade IP based solutions for thetransport network, which may be of particular importance for Hetnetsolutions.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will now be described in more detail in relation to theaccompanying drawings, in which:

FIG. 1a is a flowchart of a method performed by an RBS for transmittingdata to a UE, according to an exemplifying embodiment.

FIG. 1b is a flowchart of a method performed by an RBS for transmittingdata to a UE, according to yet an exemplifying embodiment.

FIG. 1c is a flowchart of a method performed by an RBS for transmittingdata to a UE, according to still an exemplifying embodiment.

FIG. 2 is a flowchart of a method performed by an RNC for transmittingdata to a UE, according to an exemplifying embodiment.

FIG. 3 is a block diagram of an RBS adapted for transmitting data to aUE, according to an exemplifying embodiment.

FIG. 4 is a block diagram of an RNC adapted for transmitting data to aUE, according to an exemplifying embodiment.

FIG. 3 is a block diagram of an RBS adapted for transmitting data to aUE, according to an exemplifying embodiment.

FIG. 5 is a block diagram of an RBS for transmitting data to a UE,according to an exemplifying embodiment.

FIG. 6 is a block diagram of an RNC for transmitting data to a UE,according to an exemplifying embodiment.

FIG. 7 is a block diagram of an arrangement in an RBS for transmittingdata to a UE, according to an exemplifying embodiment.

FIG. 8 is a block diagram of an arrangement in an RNC for transmittingdata to a UE, according to an exemplifying embodiment.

DETAILED DESCRIPTION

Briefly described, an RBS and a method performed by the RBS fortransmitting data to a UE, the RBS receiving frames from a network nodeby means of a Radio Link Control, RLC, protocol, are provided. Furtheran RNC and a method performed by the RNC for transmitting data to a UEvia a, RBS employing a transport protocol, the RNC transmitting data bya series of frames to the RBS to be forwarded to the UE, are provided.

In the case of data being transmitted with RLC Unacknowledged Mode,there is the risk that data delivered to higher layers in UE carriedover channels such as Common Control Channel, CCCH, Dedicated ControlChannel, DCCH, and Dedicated Traffic Channel, DTCH, etc. may arrive OOSsince the 3rd Generation Partnership Project, 3GPP RLC protocolspecification only specifies re-ordering for the Multicast ControlChannel, MCCH, and Multicast Traffic Channel, MTCH. This could lead tohigher layer protocol errors since higher layers such as RRC aresensitive to the order in which messages are received and consequentlyrely on RLC delivering data in sequence.

In the case of data being transmitted with RLC acknowledged mode thereis little risk of OOS delivery, unless this has been explicitlyconfigured, to higher layers. However, there is a risk of unnecessaryRLC retransmissions since the receiving RLC entity will immediatelytrigger the transmission of an RLC status report, unless delayed by theRLC status prohibit timer, requesting retransmissions if missing RLCacknowledged mode data is detected.

Consequently, if data is conveyed from the RBS to the RLC layer in UE,OOS may result in an unnecessary load on both the TN and radio interfacesince additional redundant copies of RLC acknowledged mode data will besent for data which was merely delayed, not lost.

There may also be a negative impact on downlink Flow Control, FC, orActive Queue Management, AQM, functions since some FC and AQM schemesrely on monitoring Iub frame losses to detect sign of TN congestion.Some of these schemes will consequently react on missing frame SequenceNumber, SN, as a sign of losses and interpret this as congestion anderroneously indicate congestion to these mechanisms thereby leading toan unwanted restriction of the data sent in TN.

Embodiments of a method performed by an RBS for transmitting data to aUE, the RBS receiving frames from a network node by means of an RLCprotocol, will now be described with reference to FIGS. 1a -1 c.

FIG. 1a illustrates the method comprising receiving 110 a frame F1 fromthe network node, the frame having a sequence number, N. If the lastreceived frame F0, prior to the received frame F1, has a sequence numberlower than N−1, then the method comprises starting 120 a first timer T1having a predefined length in time and temporarily storing 130 thereceived frame F1. If a subsequent frame F2 having a sequence numberlower than N and higher than the sequence number of frame F0 is received140, then the received frame F2 is stored 150. When all frames havingsequence number between the sequence number of frame F0 and N have beenreceived during the predefined length of the first timer T1, then themethod comprises forwarding 160 the stored frames and/or received framesto the UE in the order of the sequence numbers.

The RBS may receive one or more sequences comprising a plurality offrames from the network node to be forwarded to the UE. A sequence offrames comprises frames having individual sequence numbers, SNs.

As illustrated in FIG. 1a , for a sequence of frames, the RBS receives aframe referred to as F1. Prior to receiving the frame F1, the RBS hasreceived a frame referred to as F0. The RBS compares the sequence numberof F1 and the sequence number of F0. The sequence number of F1 isreferred to as N. If frame F1 is received in sequence with F0, then thesequence number of F0 is 1 less than the sequence number of F1. Thus, ifthe sequence number of F1 is N then the sequence number of F0 is N−1.Looking at FIG. 1a , if this is the case, then the frame, F1, isforwarded to the UE in step 160.

However, in case an out of sequence, OSS, situation has occurred, thenthere is at least one frame missing between F0 and F1. In other words,the sequence number of F0 is lower than N−1. If this is the case, thenthe first timer T1 is started in step 120. T1 has a predefined length soit will run for a predetermined period of time. The RBS then stores thereceived frame F1 and waits for the frame, or frames, that are missing.

In step 140, the RBS receives a further, or next, frame. Here it isassumed that the timer T1 is still running. Should the timer T1 expirebefore the next frame is received, then other measures are taken whichwill be explained in more detail below. Once the RBS receives thefurther, or next, frame in step 140, the RBS checks that the sequencenumber of this received frame is between the sequence number of F0 andF1. This is because since there is at least one frame missing between F0and F1, since the sequence number of F0 is less than N−1.

If this condition is fulfilled, then the received frame is stored instep 150 and the RBS checks if all frames have been received, i.e. allframes between F0 and F1. If they have, then the RBS forwards the framesto the UE in the order of the sequence numbers. For example, if therewas just one frame missing, FX, between frame F0 and F1, then the RBSforwards the frames to the UE in the order of the sequence numbers, F0,FX and F1. The RBS may also here stop the timer T1. Should the conditionin 141 not be fulfilled, i.e. the sequence number of FX not be betweenthe sequence numbers of F0 and F1, then other measures are taken whichwill be explained in more detail below.

In case not all frames are received, i.e. there are at least two framesmissing between F0 and F1, then the RBS waits to receive yet a further,or next, frame and receives it in step 140. Then the same procedure isrepeated with step 141, 150, 151 is repeated as described above. If allframes are received now, then the frames are forwarded to the UE asdescribed above, or, if T1 has not expired, then the RBS again waits toreceive a further, or next, frame.

The RLC protocol may operate in acknowledged mode, unacknowledged modeor transparent mode.

The method performed by the RBS may have several advantages. Onepossible advantage is that frames may be delivered in the correctsequence order and a possible OOS may be avoided. The method has noimpact on other nodes or entities than the RBS, hence only a softwareupdate of the RBS is required to upgrade the RBS. The method maysimplify the use of e.g. IP based solutions for the traffic network,which may be of particular importance for Hetnet solutions.

The network node may be a Radio Network Controller, RNC, and wherein theRBS and the RNC are operative to be employed in a Wideband Code DivisionMultiple Access, WCDMA, communication network.

There are several techniques for wireless communication networks, e.g.Global System for Mobile communications, GSM, employing a Time DivisionMultiple Access, TDMA, solution for the radio access, Universal MobileTelecommunication System, UMTS, employing WCDMA and Long Term Evolution,LTE, employing Orthogonal Frequency Division Multiplexing. The networknode from which the RBS receives frames to be forwarded to the UE may bean RNC, wherein the RBS and the RNC are operative to be employed in aWCDMA communication network.

The method may further comprise, if the first timer T1 expired beforeall frames having sequence number between the sequence number of frameF0 and N were received, notifying 170 higher layer of a communicationnetwork in which the RBS is employed informing that an Out Of Sequence,OSS, situation has occurred.

It may happen that not all frames are received until the timer T1expires. For example, after frame F1 has been received, T1 is started instep 120 and frame F1 is stored in 130. Then the in 140, the RBS waitsto receive a further frame. If a further frame is received, then the RBSchecks the sequence number of the received frame against the sequencenumber of F1 and F0 as described above. However, T1 may expire while theRBS is waiting to receive a further frame in 140. If so, the RBSnotifies higher layer of the communication network, in step 170, thatthe OOS situation has occurred. This scenario is indicated in FIG. 1awith the dotted line between box 140 and 152. This may happen if themissing frame or frames are permanently lost, or if they are delay to anextent so that T1 expires before all missing frames are received.

The method may further comprise forwarding 160 the stored frames and/orreceived frames to the UE.

Even if not all frames have been received before T1 expires as describedabove, the RBS may still forward the frames it has received to the UE,preferably in the of the sequence numbers. In this manner, the RBSleaves it up to the UE to deal with the fact that it does not receiveall frames. The UE may for example send ACKs for received frames and/orsend negative ACKs, NACKs, for frames not received. Whatever action theUE may take upon the reception of only parts of the frames of asequence, is of no concern for the method performed by the RBS.

The method may further comprise receiving 155 a frame F3 from thenetwork node having a sequence number higher than N+1 during theduration of the first timer T1, starting 180 a second timer T2 having apredefined length in time and storing 190 the received frame havingsequence number higher than N in the memory.

During the running of T1, the RBS may receive a further frame, F3, instep 140 having a sequence number not between the sequence number of F0and F1. In step 141 of FIG. 1a , this results in checking if thesequence number of F3 is just one above the sequence number of F1 ormore than one above. Looking at FIG. 1b , the RBS checks if the sequencenumber of the received further frame, F3, is higher than N+1. If so, itmeans that there are frame missing between F1 and the received furtherframe, F3.

Merely as an example, assume that the RBS first receives a frame havingsequence number 1 from the RNC. In step 110, since it is the first frameof the sequence, the frame is forwarded to the UE in step 160. Then thenext frame to be received in step 110 has sequence number 2. Thus alsothis frame is forwarded to the UE. Next, a further frame having sequencenumber 3 is received and is forwarded to the UE. Thereafter, frame 6 isreceived, i.e. a frame having sequence number 6. In this example, F0 isframe 3, i.e. the frame having sequence number 3 and frame F1 is frame6. Since 3<6-1, the first timer T1 is started in 120 and the frame isstored in 130. The RBS is waiting to receive a further frame andreceived the further frame in 140. In this example, the received frameis referred to as F3 and has sequence number 8. In step 141, it isconcluded that 8 is not between 3 and 6, and hence in step 155, in FIG.1b , it is checked if 8>6+1. I.e. is sequence number of F3 (8) higherthan sequence number of F1 (6)+1. Since this is true, a second timer T2is started in step 180. The second timer T2 is thus associated with themissing frame between F1 and F3, which in this example is the framehaving sequence number 7. Then the received frame, F3, having sequencenumber 8 is stored in step 190.

FIG. 1b does not illustrate what happens thereafter. However, There willbe a similar “process” associated with timer T2 as with timer T1described above. In other words, during the duration of T2, the RBS willwait to receive a further frame, in this process associated with timerT2, the further frame is frame 7, i.e. the frame having sequence number7.

Consequently, there may be more than one timer running, or processesrunning, concurrently.

According to an example, the method may comprise starting more than twotimers T1 and T2. For example, during the running of timer T2, a frameis received out of sequence with regards to the frames associated withtimer T2. Then a timer T3 may be started in the same manner as fortimers T1 and T2. Alternatively, the RBS may choose to not have morethan two timers running at the same time so that if a frame is receivedout of sequence with regards to the frames associated with timer T2,then either T1 is stopped and T3 is started and the OSS situationreported to higher layers, T2 is stopped and T3 is started and the OSSsituation reported to higher layers or no further timer, i.e. T3 is notstarted and T1 and T2 are left running and the OSS situation reported tohigher layers.

The method may further comprise receiving 155 a frame F3 from thenetwork node having a sequence number equal to N+1 during the durationof the first timer T1, storing 156 the received frame F3 and updating aparameter, upper sequence number, from N to N+1, wherein if receiving afurther frame, the sequence number of the received further frame ischecked if being between the sequence number of frame F0 and N+1.

In case the received frame, F3 has sequence number equal to N+1, thenframe F3 is in sequence with F1, meaning there are no frames missingbetween frame F1 and F3. Thus, the parameter upper sequence number isupdated from having the sequence number of F1 to having the sequencenumber of F3. The parameter upper sequence number is used in step 141,when checking whether a further received frame has sequence numberbetween F0 and F1. Since F1 has sequence number N, the parameter uppersequence number has the value N. However, if frame F3 is in sequencewith F1, then the parameter upper sequence number is updated to N+1.

Reverting to the above example, wherein frames 1, 2 and 3 are receivedin sequence and then frame 8 is received. By frame 1, 2, 3 and 6 ismeant the frames having sequence number 1, 2, 3 and 6 respectively. Whenin step 140 waiting to receive a further frame and receiving frame F3having sequence number 7, thus also being referred to as frame 7, theRBS checks in step 141 if 7 is between 3 and 6. Since it is not, the RBSchecks in step 155 if 7 is 6+1. Since this is true, the RBS stored thereceive frame 7, i.e. F3, and changes, or updates the parameter uppersequence number from 6 to 7. This means that now frames 1, 2, 3, 6 and 7have been received and in step 151 it is ascertained that not all frameshave been received since 4 and 5 are still missing. The RBS furtherascertains that the timer T1 is still running and then waits to receivea further frame and receives a further frame in 140. Assume this furtherframe has sequence number 4. The RBS checks, in step 141 is 7 is between3 and 7 (not 6 since the RBS uses the parameter upper sequence numberwhich has just been updated to 7). Since this is true, the RBS storesthe frame in step 150, checks in all frames have been received in step151. Since the RBS is still missing frame 5, the RBS checks in T1 isstill running and if so, waits for a further frame in step 140.

Still further, the method may comprise determining 111 the number ofmissing frames based on the sequence number of frame F0 and F1, andstarting 121 a respective timer T1 for each missing frame.

In this embodiment, instead of starting one timer T1 for at least onemissing frame, even if there are many frames missing, the RBS starts onetimer T1 for each missing frame.

Reverting again to the example above, assume the RBS has received frames1, 2 and 3 when frame 6 is received in step 110, FIG. 1c illustratesthat the RBS determines the number of missing frame, step 111, in theabove example, frames 4 and 5 are missing. Thus, the RBS starts tworespective timers T1 in step 121, one timer T1 for frame 4 and one timerT1 for frame 5. In this manner, two parallel processes are running foreach respective missing frame. So in FIG. 1c , To 130″ indicates thatthe next method step is 130, storing the received frame, i.e. frame 6.Then the RBS waits to receive a further frame in step 140, the furtherframe being 4 or 5 in this example. When the further frame is received,the RBS checks in step 141 if the frame number of the received frame is4 or 5. If so, e.g. the received frame has sequence number 4, then theframe is stored in step 150 and the timer T1 associated with frame 4 isstopped (not shown in FIG. 1a ) and the RBS checks in step 151 if allframes are received, which is not the case so far and thus the RBSchecks if any timer T1 is still running. Since timer T1 associated withframe 5 is still running, then the RBS waits to receive a further framein step 140. Assume further in this example that the RBS receives frame5 and then checks in step 141 if the sequence number, being 5, isbetween 3 and 6. Since this is true the RBS then checks if all frameshave been received in step 151, which is true and then the RBS forwardsto the UE in the order of the sequence numbers, i.e. 1, 2, 3, 4, 5 and6.

It shall be pointed out that the RBS may receive a frame having sequencenumber higher than 6 in the example above, wherein the RBS checks if thereceived frame has a sequence number higher than N+1 (i.e. higher than 7following the example above). If so, the actions according to steps 156or 180 are taken as described above, also in the embodiment of having arespective timer T1 for each missing frame.

The predefined value of the first and the second timer T1 and T2 may behard coded into the RBS.

The values of T1 and T2 may be hard coded into the RBS meaning e.g. thatthey are pre-programmed into the RBS upon manufacturing of the RBS. Theymay also be hard coded into the RBS by meaning of being defined uponinstallation of the RBS into the wireless network. T1 and T2 may havethe same value or they may have different values.

The predefined value of at least one of the first and the second timerT1 and T2 may dynamically determined.

Alternatively, the respective value of T1 and T1 may be dynamicallydetermined based on e.g. different characteristics of the communicationnetwork, traffic situation, load situation, interference situation andso on. They may be set e.g. in an RNC or in a Operation, Administrationand Maintenance, OAM, node and signalled to the RBS.

The timers T1 and T2 may e.g. be gradually increased with an increasingdelay for OSS delivered data.

The value of at least one of the timers T1 and T2 may be determinedbased on delay characteristics of the received frames and/or trafficnetwork statistics.

There different factors that may be relevant for the determination ofthe length of T1 and T1. One example is delay characteristics of thereceived frames. If there is a relatively large delay of the receivedframes, then the length of timers T1 and T2 may be relatively longcompared to a situation wherein there is a relatively short delay of thereceived frames, wherein the length of timers T1 and T2 may berelatively short. Another example is traffic network statistics. In casethere is a relatively high load in the communication network, or on theRBS itself, the length of T1 and T2 may be relatively long compared to asituation wherein there is a relatively low load in the communicationnetwork, or on the RBS itself, wherein the length of T1 and T2 may berelatively short.

Still further, the method may be performed per Radio Access Bearer, RAB,or Priority Queue, PQ.

An RBS may have a plurality of RABs set up and a plurality of PQs. Ifthe RBS has more than one RAB set up, then the method may be performedper RAB. Further, if there is more than one PQ, then the method may beperformed per PQ. Further, there may be more than one PQ per RAB. Thelength of the different timers, T1 and T2 may be the same or differentfor individual RABs and/or PQs.

The method may further comprise decoding Media Access Control PacketData Unit, MAC-d PDU of received frames to deduce RLC sequence numbercomprised therein and determining that an OSS situation has occurredbased on the RLC sequence number.

Instead of, or complementary to, looking at the sequence numbers of thereceived frames, the RBS may decode the MAC-d PDU of received frames. Inthis manner, the RBS is enabled to read, or deduce, the RLC sequencenumber information contained in these to determine the correct order tosend these MAC-d PDUs to the UE.

Embodiments herein also relate to a method performed by a Radio NetworkController, RNC, for transmitting data to a UE, via a RBS employing atransport protocol, the RNC transmitting data by a series of frames tothe RBS to be forwarded to the UE. Embodiments of such a method will nowbe described with reference to FIG. 2.

FIG. 2 illustrates the method comprising receiving 210 a notificationfrom the RBS indicating that an Out Of Sequence has occurred for theseries of frames; increasing 220 a frame size in order to reduce thenumber of frames; and transmitting 230 the data using the increasedframe size.

If the RBS determines that an OSS has occurred, the RBS may notifyhigher layers thereof as described above. The reason for the OSS may beassociated to different circumstances, e.g. high load. In order toincrease the probability of successful transmission of the data to theRBS, the RNC increases the frame size in order to reduce the number offrames. It may be that instead of sending a plurality of different smallframes, wherein one or two frames are lost, a few larger frames may bemore probable to reach the RBS. Thus the RNC increases the frame sizeand then transmits the data to the RBS using the increased frame size.

The method performed by the RNC may have several advantages. Onepossible advantage is that the probability of OSS occurring may bereduced and then the frames may be delivered in the correct sequenceorder and a possible OOS may be avoided. The method may simplify the useof e.g. internet grade IP based solutions for the transport network,which may be of particular importance for Hetnet solutions.

The UE may further be mandated for HSDPA channels, wherein the UEperforms the re-ordering of received frames. The UE may implement themethod above, wherein the UE detects at least one missing frame and thentemporarily stores last received frame, starts a timer, and waits toreceive the missing frame or frames. The UE does not encode or read theframes until all frames in the sequence are received.

Embodiments herein also relate to a RBS adapted for transmitting data toa UE, the RBS receiving frames from a network node by means of an RLCprotocol. The RBS has the same objects, technical features andadvantages as the method performed by the RBS as described above. TheRBS will hence on be described in brief in order to avoid unnecessaryrepetition.

FIG. 3 is a block diagram of an RBS adapted for transmitting data to aUE, according to an exemplifying embodiment. FIG. 3 illustrates the RBS300 comprising a processor 321 and a memory 322, the memory comprisinginstructions which when executed by the processor causes the RBS 300 toreceive a frame F1 from the network node, the frame having a sequencenumber, N. The memory further comprises instructions which when executedby the processor causes the RBS 300 to start a first timer T1 having apredefined length in time and temporarily store the received frame F1,if the last received frame F0, prior to the received frame F1, has asequence number lower than N−1; and if receiving a subsequent frame F2having a sequence number lower than N and higher than the sequencenumber of frame F0, then to store the received frame F2. The memoryfurther comprises instructions which when executed by the processorcauses the RBS to forward the stored frames and/or received frames tothe UE in the order of the sequence numbers, when all frames havingsequence number between the sequence number of frame F0 and N have beenreceived during the predefined length of the first timer T1.

The RBS has the same possible advantages as the method performed by theRBS. One possible advantage is that frames may be delivered in thecorrect sequence order and a possible OOS may be avoided. The RBSfunctionality has no impact on other nodes or entities than the RBS,hence only a software update of the RBS is required to upgrade the RBS.The RBS may simplify the use of e.g. IP based solutions for the trafficnetwork, which may be of particular importance for Hetnet solutions.

The network node may be an RNC, and wherein the RBS and the RNC areoperative to be employed in a WCDMA communication network.

According to an embodiment, the memory 322 further comprisesinstructions which when executed by the processor 321 causes the RBS 300to, if the first timer T1 expired before all frames having sequencenumber between the sequence number of frame F0 and N were received,notify higher layer of a communication network in which the RBS isemployed informing that an Out Of Sequence, OSS, situation has occurred.

According to still an embodiment, the memory 322 further comprisesinstructions which when executed by the processor 321 causes the RBS 300to forward the stored frames and/or received frames to the UE.

The memory 322 may further comprise instructions which when executed bythe processor 321 causes the RBS 300 to receive a frame F3 from thenetwork node having a sequence number higher than N+1 during theduration of the first timer T1, to start a second timer T2 having apredefined length in time and to store the received frame havingsequence number higher than N in the memory.

According to an embodiment, the memory 322 further comprisesinstructions which when executed by the processor 321 causes the RBS 300to receive a frame F3 from the network node having a sequence numberequal to N+1 during the duration of the first timer T1, to store thereceived frame F3 and updating a parameter, upper sequence number, fromN to N+1, wherein if receiving a further frame, the sequence number ofthe received further frame is checked if being between the sequencenumber of frame F0 and N+1.

The memory 322 may still further comprise instructions which whenexecuted by the processor 321 causes the RBS 300 to determine the numberof missing frames based on the sequence number of frame F0 and F1, andto start a respective timer T1 for each missing frame.

The predefined value of the first and the second timer T1 and T2 may behard coded into the RBS.

The predefined value of at least one of the first and the second timerT1 and T2 may be dynamically determined.

The value of at least one of the timers T1 and T2 may be determinedbased on delay characteristics of the received frames and/or trafficnetwork statistics.

The RBS may further be adapted to perform the method per Radio AccessBearer or Priority Queue.

According to an embodiment, the memory 322 further comprisesinstructions which when executed by the processor 321 causes the RBS 300to decode MAC-d PDU of received frames to deduce RLC sequence numbercomprised therein and to determine that an OSS situation has occurredbased on the RLC sequence number.

Embodiments herein also relate to a RNC adapted for transmitting data toa UE, via a RBS employing a transport protocol, the RNC transmittingdata by a series of frames to the RBS to be forwarded to the UE. The RNChas the same objects, technical features and advantages as the methodperformed by the RNC as described above. The RNC will hence on bedescribed in brief in order to avoid unnecessary repetition.

FIG. 4 is a block diagram of an RNC 400 adapted for transmitting data toa UE, according to an exemplifying embodiment. FIG. 4 illustrates theRNC comprising a processor 421 and a memory 422, the memory comprisinginstructions which when executed by the processor causes the RNC 400 toreceive a notification from the RBS indicating that an Out Of Sequencehas occurred for the series of frames; to increase a frame size in orderto reduce the number of frames; and to transmit the data using theincreased frame size.

The RNC has the same possible advantages as the method performed by theRNC may have several advantages. One possible advantage is that theprobability of OSS occurring may be reduced and then the frames may bedelivered in the correct sequence order and a possible OOS may beavoided. The RNC may simplify the use of e.g. internet grade IP basedsolutions for the transport network, which may be of particularimportance for Hetnet solutions.

Embodiments herein also relate to a RBS for transmitting data to a UE,the RBS receiving frames from a network node by means of an RLCprotocol. The RBS has the same objects, technical features andadvantages as the method performed by the RBS as described above and theRBS described above in conjunction with FIG. 3. The RBS will hence on bedescribed in brief in order to avoid unnecessary repetition.

FIG. 5 is a block diagram of an RBS for transmitting data to a UE,according to an exemplifying embodiment. FIG. 5 illustrates the RBS 500comprising a receiving unit 503 for receiving a frame F1 from thenetwork node, the frame having a sequence number, N; and a timer unit(504) and a storing unit 505 for, if the last received frame F0, priorto the received frame F1, has a sequence number lower than N−1, thenstarting a first timer T1 having a predefined length in time andtemporarily storing the received frame F1. If a subsequent frame F2having a sequence number lower than N and higher than the sequencenumber of frame F0 is received, then the received frame F2 is stored bymeans of the storing unit 505. The RBS further comprises a forwardingunit 506 for, when all frames having sequence number between thesequence number of frame F0 and N have been received during thepredefined length of the first timer T1, then forwarding the storedframes and/or received frames to the UE in the order of the sequencenumbers.

The RBS has the same possible advantages as the method performed by theRBS as described above and the RBS described above in conjunction withFIG. 3. One possible advantage is that frames may be delivered in thecorrect sequence order and a possible OOS may be avoided. The RBSfunctionality has no impact on other nodes or entities than the RBS,hence only a software update of the RBS is required to upgrade the RBS.The RBS may simplify the use of e.g. IP based solutions for the trafficnetwork, which may be of particular importance for Hetnet solutions.

In FIG. 5, the network RBS 500 is also illustrated comprising acommunication unit 501. Through this unit, the RBS 500 is adapted tocommunicate with other nodes and/or entities in the wirelesscommunication network. The communication unit 501 may comprise more thanone receiving arrangement. For example, the communication unit 501 maybe connected to both a wire and an antenna, by means of which the RBS500 is enabled to communicate with other nodes and/or entities in thewireless communication network. Similarly, the communication unit 501may comprise more than one transmitting arrangement, which in turn areconnected to both a wire and an antenna, by means of which the RBS 500is enabled to communicate with other nodes and/or entities in thewireless communication network. The RBS 500 further comprises a memory502 for storing data. Further, the RBS 500 may comprise a control orprocessing unit (not shown) which in turn is connected to the differentunits 503-506. It shall be pointed out that this is merely anillustrative example and the network node 500 may comprise more, less orother units or modules which execute the functions of the network node.The RBS 500 is further illustrated comprising further functionality 509.This functionality may be related to other features and/or function ofthe RBS necessary for the RBS to perform other tasks, for example ascheduler for scheduling UE transmission in uplink.

It should be noted that FIG. 5 merely illustrates various functionalunits in the RBS 500 in a logical sense. The functions in practice maybe implemented using any suitable software and hardware means/circuitsetc. Thus, the embodiments are generally not limited to the shownstructures of the RBS 500 and the functional units. Hence, thepreviously described exemplary embodiments may be realised in many ways.For example, one embodiment includes a computer-readable medium havinginstructions stored thereon that are executable by the control orprocessing unit for executing the method steps in the RBS 500. Theinstructions executable by the computing system and stored on thecomputer-readable medium perform the method steps of the RBS 500 as setforth in the claims.

Embodiments herein also relate to a RNC for transmitting data to a UE,via a RBS employing a transport protocol, the RNC transmitting data by aseries of frames to the RBS to be forwarded to the UE. The RNC has thesame objects, technical features and advantages as the method performedby the RNC as described above and the RNC described above in conjunctionwith FIG. 4. The RNC will hence on be described in brief in order toavoid unnecessary repetition.

FIG. 6 is a block diagram of an RNC 600 for transmitting data to a UE,according to an exemplifying embodiment. FIG. 6 illustrates the RNCcomprising a receiving unit 603 for receiving a notification from theRBS indicating that an Out Of Sequence has occurred for the series offrames; a sizing unit 604 for increasing a frame size in order to reducethe number of frames; and a transmitting unit 605 for transmitting thedata using the increased frame size.

The RNC has the same possible advantages as the method performed by theRNC as described above and the RNC described above in conjunction withFIG. 4. One possible advantage is that the probability of OSS occurringmay be reduced and then the frames may be delivered in the correctsequence order and a possible OOS may be avoided. The RNC may simplifythe use of e.g. internet grade IP based solutions for the transportnetwork, which may be of particular importance for Hetnet solutions.

In FIG. 6, the RNC 600 is also illustrated comprising a communicationunit 601. Through this unit, the RNC 600 is adapted to communicate withother nodes and/or entities in the wireless communication network. Thecommunication unit 601 may comprise more than one receiving arrangement.For example, the communication unit 601 may be connected to both a wireand an antenna, by means of which the RNC 600 is enabled to communicatewith other nodes and/or entities in the wireless communication network.Similarly, the communication unit 601 may comprise more than onetransmitting arrangement, which in turn are connected to both a wire andan antenna, by means of which the RNC 600 is enabled to communicate withother nodes and/or entities in the wireless communication network. TheRNC 600 further comprises a memory 602 for storing data. Further, theRNC 600 may comprise a control or processing unit (not shown) which inturn is connected to the different units 603-604. It shall be pointedout that this is merely an illustrative example and the RNC 600 maycomprise more, less or other units or modules which execute thefunctions of the RNC 600. The RNC 600 is further illustrated comprisingfurther functionality 609. This functionality may be related to otherfeatures and/or function of the RNC necessary for the RNC to performother tasks, e.g. coordinating one or more RBSs.

It should be noted that FIG. 6 merely illustrates various functionalunits in the RNC 600 in a logical sense. The functions in practice maybe implemented using any suitable software and hardware means/circuitsetc. Thus, the embodiments are generally not limited to the shownstructures of the RNC 600 and the functional units. Hence, thepreviously described exemplary embodiments may be realised in many ways.For example, one embodiment includes a computer-readable medium havinginstructions stored thereon that are executable by the control orprocessing unit for executing the method steps in the RNC 600. Theinstructions executable by the computing system and stored on thecomputer-readable medium perform the method steps of the RNC 600 as setforth in the claims.

FIG. 7 schematically shows an embodiment of an arrangement in an RBS700. Comprised in the arrangement in the RBS 700 are here a processingunit 706, e.g. with a DSP (Digital Signal Processor). The processingunit 706 may be a single unit or a plurality of units to performdifferent actions of procedures described herein. The arrangement in theRBS 700 may also comprise an input unit 702 for receiving signals fromother entities, and an output unit 704 for providing signal(s) to otherentities. The input unit and the output unit may be arranged as anintegrated entity as illustrated in the example of FIG. 5 and thecommunication unit 501.

Furthermore, the arrangement in the RBS 700 comprises at least onecomputer program product 708 in the form of a non-volatile memory, e.g.an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flashmemory and a hard drive. The computer program product 708 comprises acomputer program 710, which comprises code means, which when executed inthe processing unit 706 in the arrangement in the RBS 700 causes RBS toperform the actions e.g. of the procedure described earlier inconjunction with FIGS. 1a -1 c.

The computer program 710 may be configured as a computer program codestructured in computer program modules 710 a-710 e. Hence, in anexemplifying embodiment, the code means in the computer program of thearrangement in the network node 700 comprises a receiving unit, ormodule, for receiving a frame F1 from the network node, the frame havinga sequence number, N. The computer program may further comprise a timingunit, or module for starting a first timer T1 having a predefined lengthin time if the last received frame F0, prior to the received frame F1,has a sequence number lower than N−1; and a storing unit, or module, fortemporarily storing the received frame F1. If a subsequent frame F2having a sequence number lower than N and higher than the sequencenumber of frame F0 is received, then the storing unit, or module, maystore the received frame F2. The computer program may further comprise aforwarding unit, or module for forwarding (160) the stored frames and/orreceived frames to the UE in the order of the sequence numbers when allframes having sequence number between the sequence number of frame F0and N have been received during the predefined length of the first timerT1.

The computer program modules could essentially perform the actions ofthe flow illustrated in FIGS. 1a-1c , to emulate the RBS 500. In otherwords, when the different computer program modules are executed in theprocessing unit 706, they may correspond to the units 503-506 of FIG. 5.

FIG. 8 schematically shows an embodiment of an arrangement in an RNC.Comprised in the arrangement in the RNC 800 are here a processing unit806, e.g. with a DSP (Digital Signal Processor). The processing unit 806may be a single unit or a plurality of units to perform differentactions of procedures described herein. The arrangement in the RNC 800may also comprise an input unit 802 for receiving signals from otherentities, and an output unit 804 for providing signal(s) to otherentities. The input unit and the output unit may be arranged as anintegrated entity as illustrated in the example of FIG. 6 and thecommunication unit 601.

Furthermore, the arrangement in the RNC 800 comprises at least onecomputer program product 808 in the form of a non-volatile memory, e.g.an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flashmemory and a hard drive. The computer program product 808 comprises acomputer program 810, which comprises code means, which when executed inthe processing unit 806 in the arrangement in the RNC 800 causes the RNC800 to perform the actions e.g. of the procedure described earlier inconjunction with FIG. 2.

The computer program 810 may be configured as a computer program codestructured in computer program modules 810 a-810 e. Hence, in anexemplifying embodiment, the code means in the computer program of thearrangement in the RNC 800 comprises a receiving unit, or module, forreceiving a notification from the RBS indicating that an Out Of Sequencehas occurred for the series of frames; a frame size unit, or module, forincreasing a frame size in order to reduce the number of frames; and atransmitting unit, or module, for transmitting the data using theincreased frame size. The computer program modules could essentiallyperform the actions of the flow illustrated in FIG. 2, to emulate theRNC 600. In other words, when the different computer program modules areexecuted in the processing unit 806, they may correspond to the units603-605 of FIG. 6.

Although the code means in the respective embodiments disclosed above inconjunction with FIGS. 5 and 6 are implemented as computer programmodules which when executed in the respective processing unit causes theRBS and the RNC respectively to perform the actions described above inthe conjunction with figures mentioned above, at least one of the codemeans may in alternative embodiments be implemented at least partly ashardware circuits.

The processor may be a single CPU (Central processing unit), but couldalso comprise two or more processing units. For example, the processormay include general purpose microprocessors; instruction set processorsand/or related chips sets and/or special purpose microprocessors such asASICs (Application Specific Integrated Circuit). The processor may alsocomprise board memory for caching purposes. The computer program may becarried by a computer program product connected to the processor. Thecomputer program product may comprise a computer readable medium onwhich the computer program is stored. For example, the computer programproduct may be a flash memory, a RAM (Random-access memory) ROM(Read-Only Memory) or an EEPROM, and the computer program modulesdescribed above could in alternative embodiments be distributed ondifferent computer program products in the form of memories within theRBS and the RNC respectively.

It is to be understood that the choice of interacting units, as well asthe naming of the units within this disclosure are only for exemplifyingpurpose, and nodes suitable to execute any of the methods describedabove may be configured in a plurality of alternative ways in order tobe able to execute the suggested procedure actions.

It should also be noted that the units described in this disclosure areto be regarded as logical entities and not with necessity as separatephysical entities.

While the embodiments have been described in terms of severalembodiments, it is contemplated that alternatives, modifications,permutations and equivalents thereof will become apparent upon readingof the specifications and study of the drawings. It is thereforeintended that the following appended claims include such alternatives,modifications, permutations and equivalents as fall within the scope ofthe embodiments and defined by the pending claims.

1. A method performed by a Radio Base Station (RBS) for transmittingdata to a User Equipment (UE), the RBS receiving frames from a networknode by means of a Radio Link Control (RLC) protocol, the methodcomprising: receiving a frame F1 from the network node, the frame havinga sequence number N; if a last received frame F0, the frame F0 receivedprior to the received frame F1, has a sequence number lower than N−1,then starting a first timer T1 having a predefined length in time andtemporarily storing the received frame F1; if a subsequent frame F2 isreceived having a sequence number lower than N and higher than thesequence number of frame F0, then storing the received frame F2; andwhen all frames having a sequence number between the sequence number offrame F0 and frame N have been received during the predefined length ofthe first timer T1, then forwarding the stored frames and/or receivedframes to the UE in the order of the sequence numbers.
 2. The methodaccording to claim 1, wherein the network node is a Radio NetworkController (RNC) and wherein the RBS and the RNC are operative to beemployed in a Wideband Code Division Multiple Access (WCDMA)communication network.
 3. The method according to claim 1, furthercomprising, if the first timer T1 expired before all frames having asequence number between the sequence number of frame F0 and N werereceived, notifying a higher layer of a communication network in whichthe RBS is employed informing that an Out Of Sequence (OSS) situationhas occurred.
 4. The method according to claim 3, further comprisingforwarding the stored frames and/or received frames to the UE.
 5. Themethod according to claim 1, further comprising receiving a frame F3from the network node having a sequence number higher than N+1 duringthe duration of the first timer T1, starting a second timer T2 having apredefined length in time and storing the received frame having sequencenumber higher than N.
 6. The method according to claim 1, furthercomprising receiving a frame F3 from the network node having a sequencenumber equal to N+1 during the duration of the first timer T1, storingthe received frame F3 and updating an upper sequence number parameterfrom N to N+1, wherein if receiving a further frame, the sequence numberof the received further frame is checked if being between the sequencenumber of frame F0 and N+1.
 7. The method according to claim 1, furthercomprising determining a number of missing frames based on the sequencenumber of frame F0 and frame F1, and starting a respective timer T1 foreach missing frame.
 8. The method according to claim 5, wherein thepredefined length of the first timer T1 and the second timer T2 are hardcoded into the RBS.
 9. The method according to claim 5, wherein thepredefined length of at least one of the first timer T1 and the secondtimer T2 is dynamically determined.
 10. The method according to claim 9,wherein the predefined length of at least one of the first timer T1 andthe second timer T2 is determined based on delay characteristics of thereceived frames and/or traffic network statistics.
 11. The methodaccording to claim 1, wherein the method is performed per Radio AccessBearer or Priority Queue.
 12. The method according to claim 1, furthercomprising decoding Media Access Control Packet Data Unit (MAC-d PDU) ofreceived frames to deduce RLC sequence number comprised therein anddetermining that an OSS situation has occurred based on the RLC sequencenumber.
 13. A method performed by a Radio Network Controller (RNC) fortransmitting data to a User Equipment (EU) via a Radio Base Station(RBS) employing a transport protocol, the RNC transmitting data by aseries of frames to the RBS to be forwarded to the UE, the methodcomprising: receiving a notification from the RBS indicating that an OutOf Sequence has occurred for the series of frames; increasing a framesize in order to reduce a number of frames; and transmitting the datausing the increased frame size.
 14. A Radio Base Station (RBS) adaptedfor transmitting data to a User Equipment (EU), the RBS receiving framesfrom a network node by means of a Radio Link Control (RLC) protocol, theRBS comprising a processor and a memory, the memory comprisinginstructions which when executed by the processor causes the RBS to:receive a frame F1 from the network node, the frame having a sequencenumber; if a last received frame F0, the frame F0 received prior to thereceived frame F1, has a sequence number lower than N−1, then start afirst timer T1 having a predefined length in time and temporarilystoring the received frame F1; if a subsequent frame F2 is receivedhaving a sequence number lower than N and higher than the sequencenumber of frame F0, then store the received frame F2; and when allframes having a sequence number between the sequence number of frame F0and frame N have been received during the predefined length of the firsttimer T1, then forward the stored frames and/or received frames to theUE in the order of the sequence numbers.
 15. The RBS according to claim14, wherein the network node is a Radio Network Controller (RNC) andwherein the RBS and the RNC are operative to be employed in a WidebandCode Division Multiple Access (WCDMA) communication network.
 16. The RBSaccording to claim 14, wherein the memory further comprises instructionswhich when executed by the processor causes the RBS to, if the firsttimer T1 expired before all frames having a sequence number between thesequence number of frame F0 and frame N were received, notify a higherlayer of a communication network in which the RBS is employed to informthat an Out Of Sequence (OSS) situation has occurred.
 17. The RBSaccording to claim 16, wherein the memory-further comprises instructionswhich when executed by the processor causes the RBS to forward thestored frames and/or received frames to the UE.
 18. The RBS according toclaim 14, wherein the memory further comprises instructions which whenexecuted by the processor causes the RBS to receive a frame F3 from thenetwork node having a sequence number higher than N+1 during theduration of the first timer T1, to start a second timer T2 having apredefined length in time and to store the received frame havingsequence number higher than N in the memory.
 19. The RBS according toclaim 14, wherein the memory further comprises instructions which whenexecuted by the processor causes the RBS to receive a frame F3 from thenetwork node having a sequence number equal to N+1 during the durationof the first timer T1, to store the received frame F3 and update anupper sequence number parameter from N to N+1, wherein if receiving afurther frame, the sequence number of the received further frame ischecked for being between the sequence number of frame F0 and frame N+1.20. The RBS according to claim 14, wherein the memory further comprisesinstructions which when executed by the processor causes the RBS todetermine a number of missing frames based on the sequence number offrame F0 and frame F1, and to start a respective timer T1 for eachmissing frame.
 21. The RBS according to claim 18, wherein the predefinedlength of the first timer T1 and the second timer T2 are hard coded intothe RBS.
 22. The RBS according to claim 18, wherein the predefinedlength of at least one of the first timer T1 and the second timer T2 isdynamically determined.
 23. The RBS according to claim 22, wherein thepredefined length of at least one of the first timer T1 and the secondtimer T2 is determined based on delay characteristics of the receivedframes and/or traffic network statistics.
 24. The RBS according to claim14, wherein the RBS is adapted to perform the method per Radio AccessBearer or Priority Queue.
 25. The RBS according to claim 14, wherein thememory further comprises instructions which when executed by theprocessor causes the RBS to decode Media Access Control Packet Data Unit(MAC-d PDU) of received frames to deduce RLC sequence number comprisedtherein and to determine that an OSS situation has occurred based on theRLC sequence number.
 26. A Radio Network Controller (RNC) adapted fortransmitting data to a User Equipment (EU) via a Radio Base Station(RBS) employing a transport protocol, the RNC transmitting data by aseries of frames to the RBS to be forwarded to the UE, the RNCcomprising a processor and a memory, the memory comprising instructionswhich when executed by the processor causes the RNC to: receive anotification from the RBS indicating that an Out Of Sequence hasoccurred for the series of frames; increase a frame size in order toreduce a number of frames; and transmit the data using the increasedframe size. 27.-32. (canceled)